This steel rule was used in the design of early computer printouts produced by dot matrix printers. The rule has a scale of 18" along one side, divided to 1/32" for the first two inches and then to 1/16". Each inch division, up to 17, is labeled with a number of punch cards, starting with 140 cards at 1" and going up to 2,380 cards. A hole 3/16" in diameter is placed at each 1/4" and 3/4" mark up to 11-1/4" (23 holes total). These were used for setting pinfeed holes down the side of the forms for continuous feeding.
The center of the instrument has four holes 7/16" in diameter and four holes 5/8" in diameter. These are for designing holes to be punched in forms for filing. The front of the rule also has a scale of inches divided to 1/10", with subdivisions numbered from 1 to 130. This scale is a printer spacing chart, allowing the user to determine the space required for fields to be printed on the form, since each character required 1/10" of space. The rule is marked: MOORE BUSINESS FORMS, INC. Branches across the (/) United States & Canada. It is also marked at the right end: MADE IN U.S.A.
The back of the rule has a scale of inches divided to 1/12" along one edge. Along the other edge is a scale in units of 5/32" that is numbered from 1 to 100. A scale labeled "RG" has divisions the same size and is numbered from 1 to 45. This side is also marked: MOORE BUSINESS FORMS, INC. Branches across the (/) United States & Canada.
According to the donor, the 18"-size rule was considered more desirable than a 16" such as the example in the collections made by Graphic Technology (see 2006.0174.04). Fanfold paper such as that manufactured by Moore Business Forms was used from the mid-1950s into the 2000s, in association with both punched card equipment and computers.
Reference: "RR Donnelley Business Forms History," http://www.rrdonnelley.com/print-solutions/forms/history.aspx.